Loctite thread sealants loctite 142492 loctite si 5331 is designed for the locking and sealing of plastic and metal fittings carrying hot or cold water eg industrial and agricultural plastic water pipe systems and drainage systems loctite si 5331 cures at ambient temperatures under the influence of atmospheric moisture to form a low strength flexible seal loctite 142492 si 5331 thread sealant low strength 100ml